rnk created this revision.
rnk added reviewers: avt77, rsmith.
rnk added a subscriber: cfe-commits.
In dependent contexts where we know a type name is required, such as a
new expression, we can recover by forming a DependentNameType.
Works towards parsing atlctrlw.h, which is PR26748.
http://reviews.llvm.org/D20500
Files:
include/clang/Sema/Sema.h
lib/Parse/ParseDecl.cpp
lib/Sema/SemaDecl.cpp
test/SemaTemplate/ms-delayed-default-template-args.cpp
test/SemaTemplate/ms-lookup-template-base-classes.cpp
Index: test/SemaTemplate/ms-lookup-template-base-classes.cpp
===================================================================
--- test/SemaTemplate/ms-lookup-template-base-classes.cpp
+++ test/SemaTemplate/ms-lookup-template-base-classes.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++1y -fms-compatibility -fno-spell-checking -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -std=c++1y -fms-compatibility -fno-spell-checking -fsyntax-only -verify %s
template <class T>
@@ -573,3 +573,28 @@
template <typename T> decltype(h(T())) check2(); // expected-note{{candidate template ignored: substitution failure [with T = int]: no matching function for call to 'h'}}
decltype(check2<int>()) y; // expected-error{{no matching function for call to 'check2'}}
}
+
+// We also allow unqualified lookup into bases in contexts where the we know the
+// undeclared identifier *must* be a type, such as a new expression or catch
+// parameter type.
+template <typename T>
+struct UseUnqualifiedTypeNames : T {
+ _Atomic (TheType) f2; // expected-warning {{unqualified lookup}} expected-error {{no type}}
+ void foo() {
+ void *P = new TheType; // expected-warning {{unqualified lookup}} expected-error {{no type}}
+ size_t x = __builtin_offsetof(TheType, f2); // expected-warning {{unqualified lookup}} expected-error {{no type}}
+ try {
+ } catch (TheType) { // expected-warning {{unqualified lookup}} expected-error {{no type}}
+ }
+ enum E : IntegerType { E0 = 42 }; // expected-warning {{unqualified lookup}} expected-error {{no type}}
+ }
+};
+struct Base {
+ typedef int IntegerType;
+ struct TheType {
+ int f1, f2;
+ };
+};
+template struct UseUnqualifiedTypeNames<Base>;
+struct BadBase { };
+template struct UseUnqualifiedTypeNames<BadBase>; // expected-note-re 2 {{in instantiation {{.*}} requested here}}
Index: test/SemaTemplate/ms-delayed-default-template-args.cpp
===================================================================
--- test/SemaTemplate/ms-delayed-default-template-args.cpp
+++ test/SemaTemplate/ms-delayed-default-template-args.cpp
@@ -55,6 +55,15 @@
typedef int Weber;
}
+// MSVC accepts this, but Clang doesn't.
+namespace test_scope_spec {
+template <typename T = ns::Bar> // expected-error {{use of undeclared identifier 'ns'}}
+struct Foo {
+ static_assert(sizeof(T) == 4, "Bar should have gotten int");
+};
+namespace ns { typedef int Bar; }
+}
+
#ifdef __clang__
// These are negative test cases that MSVC doesn't compile either. Try to use
// unique undeclared identifiers so typo correction doesn't find types declared
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -475,6 +475,8 @@
ParsedType Sema::ActOnDelayedDefaultTemplateArg(const IdentifierInfo &II,
SourceLocation NameLoc) {
+ assert(getLangOpts().MSVCCompat && "shouldn't be called in non-MSVC mode");
+
// Accepting an undeclared identifier as a default argument for a template
// type parameter is a Microsoft extension.
Diag(NameLoc, diag::ext_ms_delayed_template_argument) << &II;
@@ -500,6 +502,50 @@
return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
}
+static const CXXRecordDecl *
+findRecordParentWithDependentBases(const DeclContext *DC) {
+ for (;; DC = DC->getLookupParent()) {
+ DC = DC->getPrimaryContext();
+ if (auto *RD = dyn_cast<CXXRecordDecl>(DC))
+ if (RD->hasAnyDependentBases())
+ return RD;
+ }
+ return nullptr;
+}
+
+ParsedType Sema::ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
+ SourceLocation NameLoc) {
+ assert(getLangOpts().MSVCCompat && "shouldn't be called in non-MSVC mode");
+
+ const CXXRecordDecl *RD = findRecordParentWithDependentBases(CurContext);
+ if (!RD)
+ return ParsedType();
+
+ // Diagnose that this identifier was undeclared, and retry the lookup during
+ // template instantiation.
+ Diag(NameLoc, diag::ext_undeclared_unqual_id_with_dependent_base) << &II
+ << RD;
+
+ // Build a DependentNameType that will perform lookup into RD at instantiation
+ // time.
+ NestedNameSpecifier *NNS = NestedNameSpecifier::Create(
+ Context, nullptr, RD->isTemplateDecl(), RD->getTypeForDecl());
+ QualType T = Context.getDependentNameType(ETK_None, NNS, &II);
+
+ // Build type location information. We synthesized the qualifier, so we have
+ // to build a fake NestedNameSpecifierLoc.
+ NestedNameSpecifierLocBuilder NNSLocBuilder;
+ NNSLocBuilder.MakeTrivial(Context, NNS, SourceRange(NameLoc));
+ NestedNameSpecifierLoc QualifierLoc = NNSLocBuilder.getWithLocInContext(Context);
+
+ TypeLocBuilder Builder;
+ DependentNameTypeLoc DepTL = Builder.push<DependentNameTypeLoc>(T);
+ DepTL.setNameLoc(NameLoc);
+ DepTL.setElaboratedKeywordLoc(SourceLocation());
+ DepTL.setQualifierLoc(QualifierLoc);
+ return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
+}
+
/// isTagName() - This method is called *for error recovery purposes only*
/// to determine if the specified name is a valid tag name ("struct foo"). If
/// so, this returns the TST for the tag corresponding to it (TST_enum,
Index: lib/Parse/ParseDecl.cpp
===================================================================
--- lib/Parse/ParseDecl.cpp
+++ lib/Parse/ParseDecl.cpp
@@ -2986,14 +2986,21 @@
Actions.getTypeName(*Tok.getIdentifierInfo(),
Tok.getLocation(), getCurScope());
- // MSVC: If we weren't able to parse a default template argument, and it's
- // just a simple identifier, create a DependentNameType. This will allow
- // us to defer the name lookup to template instantiation time, as long we
- // forge a NestedNameSpecifier for the current context.
- if (!TypeRep && DSContext == DSC_template_type_arg &&
- getLangOpts().MSVCCompat && getCurScope()->isTemplateParamScope()) {
- TypeRep = Actions.ActOnDelayedDefaultTemplateArg(
- *Tok.getIdentifierInfo(), Tok.getLocation());
+ if (!TypeRep && getLangOpts().MSVCCompat) {
+ if (DSContext == DSC_type_specifier) {
+ // Lookup failed in a context where we know we need a type. Try to
+ // recover if this was type from a dependent base class.
+ TypeRep = Actions.ActOnMSVCUnknownTypeName(*Tok.getIdentifierInfo(),
+ Tok.getLocation());
+ } else if (DSContext == DSC_template_type_arg &&
+ getCurScope()->isTemplateParamScope()) {
+ // If we weren't able to parse a default template argument, and it's
+ // just a simple identifier, create a DependentNameType. This will
+ // allow us to defer the name lookup to template instantiation time,
+ // as long we forge a NestedNameSpecifier for the current context.
+ TypeRep = Actions.ActOnDelayedDefaultTemplateArg(
+ *Tok.getIdentifierInfo(), Tok.getLocation());
+ }
}
// If this is not a typedef name, don't parse it as part of the declspec,
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -1535,6 +1535,8 @@
/// other template arguments.
ParsedType ActOnDelayedDefaultTemplateArg(const IdentifierInfo &II,
SourceLocation NameLoc);
+ ParsedType ActOnMSVCUnknownTypeName(const IdentifierInfo &II,
+ SourceLocation NameLoc);
/// \brief Describes the result of the name lookup and resolution performed
/// by \c ClassifyName().
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